This Diamond Planet Will Last Forever

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Astronomers have found the remains of a once-massive star, now
transformed into a solid diamond five times bigger than Earth.

The object circles a pulsing companion star about 4,000 light
years from Earth in the constellation Serpens (The Snake), which
lies about one-eighth of the way toward the center of the Milky
Way galaxy.

Astronomers noticed that the steady pulses of energy coming from
the star, known as J1719-1438, were regularly and minutely
disturbed, a phenomenon caused by the gravitational tug of
another, smaller circling object.

By measuring the pattern, scientists were able to figure out how
far away the second object circles and its mass, leading to the
realization that they had found a bizarre binary system, with one
partner reduced to a diamond core.

"In this case, something with the mass of our sun has evolved to
be something the mass of a planet -- quite extraordinary,"
astronomer Michael Keith, with the Australia Telescope National
Facility, wrote in an email to Discovery News.

The companion to J1719-1438 never got big enough to produce
elements much heavier than carbon, so after its lighter-weight
hydrogen and helium were stripped away that would leave a solid
core of carbon -- diamond.

"Due to the immense pressure, the carbon will be in a dense
crystal-like structure, although much more closely packed than in
a diamond on Earth," Keith said.

The system is now stable, with no evidence that it will change
for billions of years.

"Of course, this also means that it could well have been around
for a long time, just waiting for us to find it. Since it's
likely to last for longer than the Earth or the sun, I would say
that in this case, a diamond really is forever," Keith said.

The diamond planet was found as part of an ongoing search for
pulsating stars, known as pulsars, which scientists like to use
as probes.

"We'd like to find a pulsar with a black hole companion," Michael
Kramer, director of the Max Planck Institute for Radio Astronomy
in Bonn, Germany, told Discovery News. "It's the exotic case that
tell us most about the laws of physics and what's going on in the
universe."